<?php
function is_valid_email($email, $test_mx = false)  
{ //字符串比对解析，与大小写无关  
 if(eregi("^([_a-z0-9-]+)(\.[_a-z0-9-]+)*@([a-z0-9-]+)(\.[a-z0-9-]+)*(\.[a-z]{2,4})$", $email)) if($test_mx)  
 {   
	list($username, $domain) = split("@", $email);   
	return getmxrr($domain, $mxrecords);   
 }   
	else   
		return true;   
	else   
		return false;  
}  
?>